The present invention refers to a variable reluctance motor for one or more phases of the switched type. A variable reluctance motor consists of a stator for one or more phases, in which each phase may have one or more poles, each incorporating one or more windings. In each phase, the windings are either connected in series, in parallel or in series and parallel. The stator surrounds the rotor, which generally incorporates salient teeth, which can be symmetrical but can be unsymmetrical in some motor designs in order to provide starting torque.
By feeding direct current pulses--with the aid of a so called commutation device--to each phase at certain predetermined angular intervals in the rotor, the required torque in the motor is obtained. These angular intervals in the rotor are scanned by means of a rotor-position sensor which transmits signals to a control device, which in turn controls a power-step for each phase.
For some motor applications, it is desirable to have a motor which is capable of being operated at low speed with a correspondingly higher torque. In known designs for motors, this is achieved by increasing the number of phases, and thus the number of poles on the stator. However, this results in more windings, necessitating both additional labor and more copper, in turn entailing an often considerable increase in price for the motor.
Thus, one purpose of the present invention is to present a reluctance motor with few phases in relation to its speed, that is to say, with as few windings as possible.
The purpose of the invention was to base the new motor concept on the concepts of normal reluctance motors where the stator is designed to be produced as a continuous unit with a continuous magnetic circuit and with poles oriented to the rotor. Each pole is provided with a winding as shown in FIG. 1 as well as in FIG. 2 which illustrate known motors. Such motors are considerably cheaper to produce than motors where the stator is divided into separate stator poles.